[Effect of acupuncture on the ultrastructure of neurons and astrocytes in the hippocampal dentate gyrus in rats with Alzheimer's disease induced by Aβ].

Objective: To observe the effects of acupuncture at "Baihui" (GV 20) and "Shenshu" (BL 23) on the ultrastructure of hippocampal dentate gyrus in rats with Alzheimer's disease.

Methods: Forty SPF Wistar male rats were randomly divided into a normal group, a sham operation group, a model group and an acupuncture group, 10 rats in each one. The rats in the model group and the acupuncture group were treated with injection of 5 μL Aβ at bilateral hippocampus, while the rats in the sham operation group were treated with injection of 5 μL 0.9% NaCl. Three days after modeling, the rats in the acupuncture group were treated with acupuncture at "Baihui" (GV 20) and "Shenshu" (BL 23) for 20 min, once a day, six treatments constituted a course, and totally two courses were given with an interval of 1 day between courses. The rats in the other groups received normal diet and no treatment was given. Before modeling, four days after modeling and after treatment, water maze test was performed to observe the escape latency and the number of crossing platforms. The hippocampal dentate gyrus was collected and transmission electron microscope was applied to observe the ultrastructure changes of neurons and astrocytes.

Results: ①Four days after modeling, compared with the normal group and the sham operation group, the escape latency was significantly prolonged and the number of crossing platforms was reduced in the model group (all <0.01); after treatment, compared with the model group, the escape latency was significantly reduced and the number of crossing platforms was increased in the acupuncture group (both <0.01). ②In the normal group and the sham operation group, the morphology of neurons and astrocytes was intact, the nuclear and membrane structure were clear, and the morphology of organelles such as mitochondria, endoplasmic reticulum and lysosomes was normal. In the model group, the morphology of neurons was irregular, the nucleus was severely constricted with edema in the cytoplasm, the color of heterochromatin was deepened, the endoplasmic reticulum was expanded, the granulation was removed and the number of mitochondria was decreased, even with malformed-like change in mitochondrial cristae; there was severe edema around astrocytes, few organelles in the cytoplasm, severe swelling of mitochondria and mild expansion of the endoplasmic reticulum. In the acupuncture group, the edema of the neuron and astrocytes was still evident, and the mitochondrial was mildly swollen but relieved compared with that in the model group, and there were no obvious abnormalities in neuronal endoplasmic reticulum and ribosomes.

Conclusion: Acupuncture could improve the ultrastructure of neurons and astrocytes in the hippocampal dentate gyrus in rats with Alzheimer's disease induced by Aβ.